Our research objective is to pursue our investigations of leukemia and malignant tumor therapy by participation in Children's Cancer Study Group (CCSG). This organization is composed of pediatric hematologists/oncologists, radiotherapists, surgeons, and pathologists from a number of pediatric and cancer institutions, and is involved in protocol studies of pediatric malignancy as formulated by the members of the group. The investigations include the chemotherapy, radiotherapy and immunotherapy trials in acute childhood leukemia and drug therapy trials in solid tumors of the young in conjunction with surgery and radiotherapy. Data on the natural history, complications of treatment and the survival of these patients are collected on an ongoing basis. Statistical supervision is maintained in all of the protocol studies, and in most cases these studies are randomized to prevent bias.